Added Dell EMC SC multipath support

Added a new parameter CinderDellScMultipathXfer to
support cinder::backend::dellsc_iscsi::use_multipath_for_image_xfer
to the Dell EMC SC Cinder iSCSI volume driver template.

Depends-On: https://review.openstack.org/#/c/616687/
Change-Id: I04f42ce0cd117f7dcc7a817274ea7664d9995864
(cherry picked from commit 72eea3c6ea)

environments/cinder-dellsc-config.yaml

@@ -20,3 +20,4 @@ parameter_defaults:
   CinderDellScSecondarySanPassword: ''
   CinderDellScSecondaryScApiPort: 3033
   CinderDellScExcludedDomainIp: ''
+  CinderDellScMultipathXfer: true

puppet/services/cinder-backend-dellsc.yaml

@@ -64,6 +64,9 @@ parameters:
   CinderDellScExcludedDomainIp:
     type: string
     default: ''
+  CinderDellScMultipathXfer:
+    type: boolean
+    default: true
   ServiceData:
     default: {}
     description: Dictionary packing service data
@@ -113,3 +116,4 @@ outputs:
                 cinder::backend::dellsc_iscsi::secondary_san_password: {get_param: CinderDellScSecondarySanPassword}
                 cinder::backend::dellsc_iscsi::secondary_sc_api_port: {get_param: CinderDellScSecondaryScApiPort}
                 cinder::backend::dellsc_iscsi::excluded_domain_ip: {get_param: CinderDellScExcludedDomainIp}
+                cinder::backend::dellsc_iscsi::use_multipath_for_image_xfer: {get_param: CinderDellScMultipathXfer}

releasenotes/notes/dellsc-driver-d7cd300a24a64b01.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - Added Dell EMC SC multipath support
+    This change adds support for
+    cinder::backend::dellsc_iscsi::use_multipath_for_image_xfer
+    Added a new parameter CinderDellScMultipathXfer.